1. Field of the Invention
The present invention relates to a structure for attaching a spring to be attached to two rotatable members.
2. Description of the Related Art
Conventionally, various structures such as a backrest of a chair have been suggested, which elastically urge two members supported rotatably in a predetermined direction. Among such structures, in the case of a chair that an elastic member is provided between a seat of the chair and a backrest rotatably supported against the seat, an aspect of elastically urging a backrest frame forward by a spring such as a gas spring upon the rocking operation to incline the backrest backward has been known.
Patent Document 1: Japanese Patent Application Laid-Open No. 2002-119373
On the other hand, an aspect may be considered, in which, by attaching a frame-like spring to two members rotatably attached, these members are elastically urged due to an elastic repulsion of the spring.
However, in order to attach a resin spring to two members, particular mechanical parts are required, the mechanical parts being for attaching the resin spring accurately and securely to a predetermined position in the opposite ends of the spring and an attaching part disposed to each two members for attaching the members to these opposite ends of the spring. Then, when attaching these particular mechanical parts to the members, many mechanical parts should be put on the attaching parts and the opposite ends of the spring and this increases the total number of the parts.